Microwave‐Assisted Synthesis of Heterocycles from Aryldiazoacetates**

Abstract

Herein, we describe a rapid microwave‐assisted, metal‐free synthesis of substituted quinoxalinones and quinoxalines using the carbene‐mediated reaction between aryldiazo esters and 1,2‐diamines. The reaction can encompass a range of substituents and structural variations to afford quinoxalin‐2‐ones in 14–80 % yield and corresponding quinoxalines in good to excellent yields upon oxidation (67–96 %). The approach can be employed to generate symmetrical and unsymmetrical 2,3‐diarylquinoxalines, bis‐quinoxalines as well as novel quinoxaline‐substituted diazo esters and should be a valuable addition to the heterocycle synthesis toolbox.

Facile access to C-substituted piperazin-2-ones and mianserin derivative enabled by chemoselective carbene insertion and cyclization cascade

“…Based on the previous literature reports 3,11 and our control experiments, we proposed a plausible mechanism (Scheme 4B). Initially, the copper catalyst reacts with 1a , generating a copper–carbene complex I by expelling N 2 gas.…”

Synthesis and Chemistry of Diazo Compounds under Microwave Irradiation: A Review

“…[43] A novel microwave-assisted protocol has been developed for the synthesis of quinoxalin-2-ones by the reaction of aryldiazoacetates 46 with aryl 1,2-diamines 47. [44] The reaction offered only traces of products under conventional heating at 100 °C for one hour. Usually, the reactions of α-diazocarbonyl compounds proceed through ketenes in the absence of any catalyst and via cerbenoids in the presence of metal catalysts.…”

“…A novel microwave‐assisted protocol has been developed for the synthesis of quinoxalin‐2‐ones by the reaction of aryldiazoacetates 46 with aryl 1,2‐diamines 47 [44] . The reaction offered only traces of products under conventional heating at 100 °C for one hour.…”

Microwave‐assisted Four‐component Cascade Reaction: One‐pot Rapid Access in the Metal‐free Synthesis of Fully Substituted Pyrroles

“…Because of the high reaction rate and high yields, microwave‐assisted reactions have gained popularity and have become an environmentally friendly method in the field of organic synthesis. Specifically, the groups of Hansen [14] and Anilkumar [15] have independently reported a methodology for the synthesis of heterocycles under microwave heating. Based on the development and use of simple raw materials and efficient tandem cyclization to synthesize various heterocyclic compounds in our group, we offered convenient and efficient access to some heterocycles of chemical and pharmaceutical importance [16,17] .…”